I have not explicitly tested the SC794, but it is a standard DS1302 RTC implementation which should work fine with RomWBW including the NVRAM config settings.
Regarding the NVRAM settings, note that this is a new feature. It currently just supports specifying a disk/slice to autoboot and the associated timeout. Additional options will be supported over time including things like specifying the type of floppy drives attached to your system.
Thanks, Wayne